Cross-over effects in anisotropic spin systems

Abstract

The thermodynamic properties of an anisotropic multicomponent spin system are investigated near the bicritical point in the disordered phase using a renormalization group approach. Explicit forms for the cross-over scaling functions for the specific heat and the susceptibilities are found to lowest orders in epsilon =4-d in terms of z=gt^{- phi} where g is the non-ordering field and t=(T-T_b)/T_b with T_b the bicritical temperature. The scaling functions have the expected properties in the limits z to O and z to zt/dt, the value on the critical lines, and interpolate smoothly between these limits.